Embolic material can occur in the blood in human arteries and veins. Such embolic material may have the form of thrombus, lipid, lipoprotein, calcified material, and still others. Embolic material can cause a number of well-known problems in the human body, potentially blocking blood flow to critical organs and leading to heart attack, kidney failure or stroke. Various drug therapies are used to prevent or suppress the formation of certain types of emboli, and various interventional procedures are known for eliminating or treating conditions leading to the risk of creation or release of embolic material. Various treatments, and notably implanted medical devices, however, can themselves lead to the development and/or release of embolic material into the bloodstream.
In response to a perceived need to protect against the health risks relating to embolic material in the bloodstream, a number of designs and delivery techniques for devices such as vascular filters have been proposed. In one common strategy, a vascular filter is positioned in the vena cava to capture embolic material before the embolic material can enter the heart and be conveyed to the lungs, brain or elsewhere. Such devices have begun to find relatively widespread application. One embolic protection device is known from commonly owned U.S. patent application Ser. No. 12/038,238 to Hoffman. Hoffman discloses an embolic protection device for capturing emboli, having a frame and a Z-stent waistband. Exploiting flexibility of the waistband, the embolic protection device apparently is adjustable between a collapsed state, and an expanded state for capturing emboli. While Hoffman's design may work well, there is always room for improvement.